1. Field of the Invention
The present invention relates generally to the art of doors, windows and other closures. More particularly, the present invention relates to a rigid construction (and the method for making that construction) for sliding closures designed to avoid difficulties previously experienced with such closures during sliding.
2. Description of the Prior Art
Sliding doors and windows are typically fabricated from extruded aluminum formed in a rectangular configuration. It is conventional to form a corner for such closures by cutting two lengths of the aluminum channel material with a bevel and butting the beveled cuts together to form an L-shaped corner. The corner may be fastened by L-shaped brackets on either (or both) the inside or the outside of the corner, with fasteners joining the bracket to each side of the corner.
It is also known to provide an insert having an outer diameter configured to the inner diameter of the channel, and sliding the insert into the channel to bridge the slot between the two lengths of channel material forming the corner material. The insert is then held in place by a mating extrusion or similar means.
There are certain uses of sliding closures where the above-described corner constructions have proven to be unsatisfactory. Of particular significance are uses for screened patio and porch doors designed to slide along horizontal tracks. Such doors typically have rather long vertical and horizontal dimensions, and carry a flexible material (i.e. screen) which does not impart any rigidity to the overall structure. As a result, such doors are particularly susceptible to twisting and distorting forces caused by any binding in the bottom of the track (where the weight of the door is supported). Since such doors are usually outside, binding frequently results from leaves, dust and the like which are lodged in the bottom track. When this happens, the twisting and distortion may cause the corners of the door to become out of square, resulting in binding.